The major activities during the next 5 years will deal with the elucidation of the primary structure of heavy chain disease proteins and selected regions of IgA and IgG molecules so as to gain a clearer understanding of the genetic control of immunoglobulin structure. In addition, we plan to study the structure and function of the J chain and to localize certain biologic properties to regions of the gamma chain. In addition, we plan to study the state of delayed hypersensitivity of patients with systemic lupus erythematosus and to continue our studies on the structure, pathogenesis, heterogeneity and possible origin of amyloid.